Student safety sheets 92 Using a Bunsen burner For heating non-flammable liquids and solids, see CLEAPSS Student Safety Sheet 93.

For heating flammable liquids and solids, see CLEAPSS Student Safety Sheet 94. For handling hot liquids in beakers, see CLEAPSS Student Safety Sheet 95. Using a Bunsen burner • Tie any long hair back to avoid it catching fire. • Make sure your clothing does not get in the way of the flame and don’t lean over a flame to reach other apparatus. • Wear eye protection. • Place the Bunsen burner on a heat-resistant mat 30 to 40 cm from the edge of the bench. • Make sure the air hole is closed (unless you are lighting the gas with a piezo-electric lighter, in which case air hole should be half open). • Attach the gas tubing to the gas tap. • Light a match or a wooden splint from a central flame. (Do not walk around the laboratory with wooden splint alight.) • Turn on the gas tap. • Keeping your head well away from the Bunsen burner, use the match or lighted splint to light the gas coming up the Bunsen burner chimney. • Do not allow solids to drop into the Bunsen burner to clog the gas jet or the collar at the top of the chimney. When you have finished: • Make sure the air is closed and the flame is yellow. • Switch the gas off. • Remove the tubing by putting your fingers on the tubing around the gas tap nozzle and pulling. Don’t pull the tubing off by stretching it. Types of flame from a Bunsen burner

Type of flame Gas tap Air hole Appearance Hazards When used Yellow flame Fully Closed This flame is still hot To light the burner and (or partly) if you put your hand when it is not being used open into it. to heat anything because is easy to see and will not readily set fire to clothing etc. This flame is unsuitable for heating as it coats surfaces

with soot (carbon). Gentle flame Half open Partly It is difficult to see Yellow just closed the flame in bright disappears; pale sunlight. Some risk of lilac, almost blowing out. For general heating. invisible. Start with the gentle flame Medium flame It is difficult to see Fully open Partly and then open the gas tap Yellow just the flame in bright closed fully to give the medium disappears; pale sunlight. flame. lilac, almost Some risk of blowing invisible. out.

Roaring flame Fully open Fully open It is difficult to see For very strong heating Inner cone blue, the flame in bright (which is not very often outer cone lilac. sunlight. Some risk of needed). blowing out. The hottest section of the Do not partly close flame is just above the the gas tap if the air blue cone of unburnt gas. hole is fully open as this will extinguish

the flame. Student Safety Sheets are teaching materials. For safety management, use Hazcards and other resources on the CLEAPSS website. ©CLEAPSS 2019